EIS characterisation of Ti anodic oxide porous films formed using modulated potential

Titanium, due to its excellent corrosion resistance, good mechanical properties and biocompatibility has been employed in many fields, such as in biomedical and dental implants. A passive oxide film formed on titanium surface is responsible for its high corrosion resistance. In the present study, oxide films were grown on titanium surface employing an anodising procedure using modulated potential, in a hydrofluoric acid solution. Electrochemical impedance spectroscopy was used to study the electrochemical behaviour of anodised Ti surface in a NaCl solution. The dependence of oxide film characteristics on forming conditions was analysed employing equivalent circuits. Samples were observed by scanning electron microscopy, in Jeol-JSM-5900LV microscope of the LME/LNLS, Campinas. It was observed that final anodising potential has an influence on the porous layer film morphology and that the anodising procedure with the chosen solution produces a double layer porous anodic film.